An asteroid city is a theoretical concept that involves building a human settlement on an asteroid.

This idea has been proposed as a potential solution to issues related to overpopulation, resource depletion, and environmental degradation on Earth.

The construction of an asteroid city would require a significant amount of resources and advanced technology.

The first step would be to identify a suitable asteroid that could support human life. The asteroid would need to have a stable orbit and provide enough resources for sustainable living.

The construction of an asteroid city would require the development of advanced technologies for mining, processing, and recycling resources.

The city would need to be self-sustaining and capable of producing food, water, and energy for its inhabitants.

Asteroid cities could potentially serve as a hub for space exploration and resource extraction, as they could provide a base of operations for missions to other celestial bodies.

However, the concept is still largely theoretical, and there are many technical and logistical challenges that would need to be overcome before an asteroid city could become a reality.

I assume you are referring to any notable asteroids that were discovered or had a significant event in the year 2021. Here are a few examples:

1. Asteroid 2021 EQ3: This near-Earth asteroid was discovered on March 6, 2021, by the Catalina Sky Survey in Arizona. It has an estimated diameter of 10-22 meters and passed within 380,000 km of Earth on March 8, 2021.

2. Asteroid 2021 GW4: This asteroid was discovered on April 11, 2021, by the Mt. Lemmon Survey in Arizona. It has an estimated diameter of 7-16 meters and passed within 33,000 km of Earth on April 12, 2021.

3. 2021 KT1:

4. This asteroid was discovered on May 25, 2021, by the Pan-STARRS survey in Hawaii. It has an estimated diameter of 130-280 meters and passed within 4.5 million km of Earth on May 28, 2021.

5. Asteroid 2021 PH27: This asteroid was discovered on August 14, 2021, by the Dark Energy Survey in Chile. It has an estimated diameter of 1-2 kilometers and is classified as a potentially hazardous asteroid due to its orbit and size.

Overall, there were many asteroids discovered and observed in 2021, but these are just a few notable examples.

 I can tell you that there will likely be many asteroids discovered and studied in the year 2022.

Several asteroid surveys, such as the Pan-STARRS and the Catalina Sky Survey, are continuously scanning the skies to identify new objects.

and there are also ongoing missions such as NASA’s OSIRIS-REx and Japan’s Hayabusa2 that are returning samples from asteroids.

It is also possible that there may be some asteroid close approaches to Earth in 2022.

but these cannot be predicted with certainty until they are discovered and their orbits are determined.

The good news is that NASA and other space agencies are constantly monitoring near-Earth objects and working to improve our ability to detect and track potentially hazardous asteroids.